1. Field of the Invention
The invention relates to a process for preparing toilet bars comprising as surface active components a major amount of soap and a minor amount of acyl isethionate salt.
2. The Prior Art
For many people, toilet bar and soap are synonymous terms. This derives from soap being the primary active and major component of most commercial bars. Soap has the enviable properties of being inexpensive and an efficient cleanser. Shortcomings in mildness and lather have, however, been noted. These deficiences may be remedied by replacing substantially all of the soap with sodium acyl isethionate. Some thirty years ago, a bar of this composition was successfully introduced into commerce.
Toilet bars wherein sodium acyl isethionate constitutes the major active are mild and of good lather. However, they suffer in properties where soaps perform well. Specifically, sodium acyl isethionates are soft and produce the phenomena of mush. Consequently, there have been proposals for combining the two actives in a toilet bar to achieve the desirable properties of each but avoiding their separate disadvantages.
The prior art discloses bars which contain major amounts of soap and minor amounts of sodium acyl isethionate. For instance, U.S. Pat. No. 4,260,507 reports a bar containing from 60 to 97% soap and 3 to 40% sodium acyl isethionate.
Within the literature are detailed many criticalities in the processing of toilet bars. U.S. Pat. No. 3,989,647 reports bars containing alkane sulfonate and various binder modifiers such as acyl isethionates processed with water initially added in an amount sufficient to obtain a final water content of about 5 to 25%. U.S. Pat. No. 3,376,229 discloses that bars with major amounts of sodium acyl isethionate and minor amounts of soap are best limited to a water content below 4-5% to avoid softness. Components are blended at about 235.degree. F. Dutch Patent Application No. 6603918 describes acyl isethionate, optionally combined with minor amounts of soap, being processed at temperatures from 100.degree. to 110.degree. C., the water component being controlled to obtain from 5 to 15% water in the product.
It is an object of this invention to provide a process for preparing toilet bars containing a major amount of soap and a minor amount of sodium acyl isethionate.
A further object of this invention is to obtain by this method, a toilet bar having consumer use and processing properties that fall within commercially acceptable parameters.